MOSCOW (Reuters) - Russia will give its ally Tajikistan $1.1 million to build a new outpost on the Tajik-Afghan border, a senior Russian diplomat was quoted as saying on Thursday, amid growing instability in Afghanistan as U.S.-led troops withdraw.

       The planned outpost will be located in Tajikistan's Khatlon province adjacent to Afghanistan's Kunduz province whose capital city Taliban insurgents took over this week as part of a broader offensive.

       The Russian and Tajik governments will soon sign the agreement on aid provision, Interfax quoted Deputy Russian Foreign Minister Oleg Syromolotov as saying.

       He described the location of the planned facility as one of the most vulnerable points on the Tajik-Afghan border.

       Russia operates a military base in Tajikistan, a fellow ex-Soviet republic, whose government has expressed concern about the rapidly deteriorating security situation in Afghanistan.

       Hundreds of Afghan servicemen crossed the border into Tajikistan last month, fleeing a Taliban offensive. Tajikistan later sent back the Afghan servicemen as the Kabul government arranged special flights to return them.

       Russia, Tajikistan and Uzbekistan, another Central Asian republic bordering Afghanistan, concluded joint military drills close to the Tajik-Afghan border this week and Moscow has delivered new hardware to its Tajik base to reinforce it.

       (Reporting by Olzhas Auyezov; Editing by Simon Cameron-Moore)